Automatic telephone system.



0. E. HILL. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED FEB-12,1916.

1,238,140. 5 'Patented A11g.28,1917.

UNITED STATES PATENT OFFICE.

OWEN E. HILL, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

LUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Aug. 28, 1917.

Application filed February 12, 1916. Serial No. 77,829.

i To all whom it may concern:

Be it known that I, OWEN E. HILL, a citizen ot' the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Automatic Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to automatic telephone systems in which the talking connection between subscribers lines is established wholly or in part by means of electrically operated switching devices.

One of the objects of the present invention, expressed broadly, is to provide means whereby the capacity of a switching device may be doubled without the necessity of a material increase in the operating mechanism and circuits therefor. More particularly, this object of the invention is to provide a system employing switches having a plurality of movable contacts which are adapted to be simultaneously moved over their corresponding fixed contacts, and in which the set of brushes through which the connection may be extended to a desired line is automatically determined by the manner in which the switch is selected.

Another object of the invention is the provision of means whereby the act of selecting a brush set also operates to select a particular character of ringing current.

In the drawings, the calling subscribers substation is indicated at A and the called subscriber's station at B. The brushes of a line finder switch which are associated with the terminals of the calling line are indicated at 1. Brushes 2 and 3 diagrammatically represent selector switches by means of which the calling line may be extended in any desired manner to the connector switch, the circuits of which are shown in the drawing. In the present disclosure, the invention is disclosed as applied to a two-wire multiple system similar to that shown in an application of C. L. Goodrum, Serial No. 35,326, filed June 21, 1915. It will be observed that the connecting circuit extending to the connector switch is multipled so as to provide two sets 4, 5 and (i, 7 respectively of terminal contacts.

At the right in Fig. 2 are shown the two sets of brushes of the connector switch, brushes 8 and 9 being arranged to be moved over one series or group of contacts at the same time that brushes 10 and 11 are moved over another similar set. In the present disclosureeach set of brushes simultaneously engage terminals of the same line, but it is to be understood, of course, that the contacts engaged by brushes 8 and 9 may be the terminals or a different group of lines from those engaged by brushes-10 and 11.

Nearly any switch which is provided with a series of fixed contacts and a movable contact, adapted to traverse said fixed contacts, may be employed with the present invention by an obvious modification.

The present system was especially designed for use with a switch of the general character of that shown in Patent No.

1,172,585, issued February 22, 1916, to Henry F. Dobbin. This switch is provided with five sets of brushes, and two series of contacts of ten each are provided for each of the brush sets, the two series arranged for engagement by the same brush being mounted side by side in a panel bank. The series of contacts in which a. desired line terminates, is selected by rotating the switch shaft until the brushes having access thereto are positioned under said series, and then moving the switch shaft upwardly until the llorushes reach the contacts of the desired In employing this switch with the present system, it would be modified by providing the shaft with another group of five sets of brushes and providing another terminal bank for engagement thereby. The second group of brush and the terminal bank employed would be in every-way identical in relative arrangement and operation with those shown in the above mentioned application. It is to be understood, of course, that the contact bank arranged for the upper set of brushes may represent the terminals of a different group of 100 lines from those in the lower contact bank. Thus the 100-point switch of the application to Dobbin may be transformed into a 200-poipt switch.

Switches of the character of that shown in the patent to Keith ct 01., No. 815,176, may also be employed, but it will be necessary to modify this switch by providing it with an additionalset of brushes and an additional contact bank to be traversed thereby. This would mean that the switch shaft would be extended upwardly, and a second set of brushes will be secured to said shaft in the same manner as'in the switch shown in said patent. A second terminal bank would be provided having terminals to ,be engaged by the upper set of brushes. Thus, the capacity of the switch will be increased from one which has access to but 100 lines to one having access to 200 lines. As the switch structure shown in he above noted patent to Keith et al. is well known, we will assume that such a switch modified as above described and also by the omission of the third brushes of each set and the corresponding rows of contacts, is employed herein. In the present disclosure, the brushes 10 and 11 as being the ones with which the switch was originally provided, and the brushes 8 and 9 as the additional set of brushes.

The operation of the system briefly is as follows: The brushes 3 of the selector switch will be directed onto the level in which the contacts 4 and 5 are arranged, or onto the level including the terminals 6 and 7 depending on which hundreds the called subscriber is in. brushes 3 are brought to rest on the contacts 4 and 5, the preceding connecting or trunk circuits, and thecalling subscribers substation circuit being now closed, a circuit will extend from battery through the stepping relay 15 to the upper talking conductor and thence through conductor 16-, winding of the brush selecting and ringing current selecting relay 17, to terminal 4, thence over the upper conductors of the trunks, right side of the subscribers line through the substation thereof, back over the left side of the line, through lower brush 1, to ground at 18. Relay 17 will attract its armatures, thus removing the brushes 10 and 11 from the con necting circuit and joining brushes 8 and f) to the connecting circuit.

\Vhen the subscriber operates the sending device to establish the connection, the oftnormal contact 19 of the connector switch will close, short-circuiting the left winding of relay 17, but said relay will now look up through its right winding, innermost armature and off-normal contact 20, thus insur ing that it will be maintained energized until the switch is returned to its normal position. The operation of completing the connection from its point does not materially differ from that described in the above mentioned application to (loodrum.

Assuming now thatthe line of substation A has been extended to contacts 4 and 5, the operation of the system is spcc'ilically as tollows: Upon the engagement of the terminals 4 and 5 by the brushes 3, relay l7 was encrgizod in the manner just dcscrilwd. ltclay 15 was also energized in the circuit above traced, causing the cnergization of relay 21.

we may consider.

Assuming first that the The subscriber at A now operates his dial to v produce his tGIlSJSBIlBS of impulses. This will step up the brush shaft on which the brushes 10, 11 and 8, 9,are modnted to move both sets of brushes into operative relation opposite corresponding tens series bf contacts, but of ditferent 100s. This stepping operation is effected by a circuit extending from battery through the primary magnet 22, side switch Wiper 23, innermost right armature and back contact of test relay 24, front contact and right armature of relay 21 to ground, through the back contact and armature of relay 15. As relay 1.3 will be vdei nergized with each of the openings of the substation circuit by the sending device, the circuit for stepping magnet 22 will be repeatedly established in a manner well understood.

Upon each retraction of the armature of relay 15, a circuit is also completed from battery through slow-to-release relay 25. contact and armature of relay '21 to ground. Relay 25 in attracting its armature completes a circuit for the escape magnet )6. Relay 25 being slow to release, stays up during the series of impulses. Upon the termination of the lOs series of impulses relay 15 remains energized, thus holding open the circuit for relay 25 which retracts its arma turcs, opening the circuit for the escape magnet 26 and causing the side switch to more to position 2.

The subscriber again operates his sending device to send the units series of impulses. thus stepping both the brush sets 10, 11 and S, 9 from set to set ot the contacts in their respective series. As we assumed that the brushes 3 were positioned on the upper set of contacts, relay 17 is energized. and therefore the brushes l0 and 11 arercmoved from connection to the connecting circuit.

\Vith each interruption of the subscribers line by the sending device, relay 1?) will re tract its armature as before, and complete a circuit from battery through the secondary or rotary stepping magnet .27, wiper 23, inner right armature and back contact. of relay 24, right armature and front contact of relay 21 to ground, through the armature and back contact of relay 17 Due to the repeated energization and dei ncrgization of magnet 27, the switch brushes are stopped around to the contacts of the wanted line.

The lower or test contacts of idlc lines will be connected to ground as through rclay 28. The contacts of busy lines. however, will be supplied with battery potential by a cii'cuit extending through relay 29. side switch wiper 30 and the middle right armature of the brush selecting relay 1? at the switch associated therewith. .\s will now be readily understood. it' the relay 17 at said switch is energized, it will apply busy potential to the contact engaged by its brush 8, while if the connector was selected at terminals COI'reSPOIIdiDg to the terminals 6, 7 relay 17 will not be energized and busy potential :will be supplied to the line terminal engaged by brush 10.

We will first assume that the wanted line is busy. Thus, upon the termination of the series of impulses When-relay 25 retracts its armature, a circuit will extend from battery through relay 29 of the switch previously in engagement with the line, through the side switch wiper 30 and brush 8 of said switch, thence through the multiple test contactsof the line to brush 8 of the switch herein shown, front contact and middle armature of relay 17, wiper 30 (in position 2), the right winding of relay 24 to ground, through the contact and armature o escape magnet 26, and the back contact and left armature of relay 25. Relay 24 will be energized and at its inner right armature will interrupt the stepping circuit. At its left armature it will complete a locking circuit for itself from battery through its left winding, armature and lower contact to ground through the inner left armature and contact of relay 21.

' It also completes a circuit from battery through escape magnet 26, Wiper 31, through both contacts and left armature of relay 24 and thence to ground through contact and armature of relay 21 as before. As magnet 26 is made slow to release, the circuit just traced is closed before it has retracted its aris closed from the busy tone device 32 through the contact and outermost right armature of test relay 24 to the upper talking conductor, thus notifying the calling subscriber that the wanted line is engaged.

The calling subscriber will then replace his receiver upon its hook, causing the deenergization of relay 15 which in retracting its armature in turn interrupts the circuit for rela 21. A circuit is now established Jfrom battery through the release magnet 33,

off-normal contact 34, outermost left armature and back contact of relay 35, back con tact and right armature of relay 21 to ground through the back contact and right armature of relay 15. The release magnet 33 in attracting its armature will provide a locking circuit for itself, thus insuring the return of the switch to its normal position. The retraction of the armature of relay 25, due to the deenergization of relay 21,, closes a circuit from battery through the stepping magnet 27, left armature and back contact of relay 15, outermost left armature and contact of relay 21, right armature and back contact of relay 25, and the left armature and back contact of relay 35 to the lower conductor of the trunk. This will cause an impulse to be sent over the lower conductor which may be employed to effect the release of the preceding selector switches. The idle or selectable potential for the test terminals of the connector switch of the connecting circuit, may also be supplied over the circuit just traced.

Assuming now that the wanted line is idle, the test terminal engaged by brush 3 will not be connected to battery, and therefore relay 24 will not be energized at the end of units selection. Thus, the escape magnet 26 .will retract its armatures and move the side switch to position 3. In position 3, a circuit is completed from battery through escape magnet 26, wiper 31, armature and back contact of ringing cut-oft relay 37 and the front contact and innermost left armature of relay 21 to ground. Escape magnet 26 will be energized, but will not move the side switch wipers. In this position of the side switch, another circuit is completed from battery through ringing relay 29, wiper 30, middle armature and front contact of relay 17 brush 8 and the winding of cut-ofi' relay 28 to ground. Relay 29 will be energized, completing a circuit from the.

ringing generator 38, left armature and front contact of relay 17, relay 37, armature and front contact of relay 29, wiper 39,0uter armature and front contact .of relay 17 brush 9, the leftside of the subscribers line, through the signaling apparatus thereof, back over the right side of the line to ground through relay 28. This will cause the operation of the signal device of the called subscriber.

Had the connector trunk been selected at contacts 6, 7, relay 17 would not have been energized and ringing current Would have been supplied from generator 38 through the back contact and left armature of relay 17. This permits of selecting ringing current by the operation of the brush selecting relay, and thus the parties on a multiparty line may be selectively rung merely by providing a terminal set for one party in one section of the contact bank and a set for another party in the other section of the bank.

Upon the called subscriber removing his receiver from its hook, the resistance of the circuit will be decreased, causing an increased flow of current through relay 37 which will attract its armature, thus interrupting the circuit for the escape magnet 26 and causing side switch to move to position 4.. in position 4, the talking circuit is completed between the calling and called subscribers:

WVhen the side switch moves to position 4, relay 35 is energized by a circuit from battery through relay 29, wiper 30, middle armature and front contact of relay -17, brush 8. right side of the subscribers line, substation apparatus thereat, back over the left side of the line, brush 9, front contact and outermost arn'iature or relay 17, wiper 39, and the winding, of relay 35 to ground. Thus, relay 35 will be maintained energized as long as the called subscribers substation circuit is closed.

It will be noted that the establishment of the circuit for the release magnet 33 is now dependent on the dci nergized condition of relay 35 which is controlled by subscriber B, and on the dei ncrgizml condition of relay 15 which is controlled by sul scribcr Therefore, the release of the connector switch is controlled jointly by the calling and called subscriber. It is immaterial which of the subscribers first replaces his receiver on the hook as the release circuit will be held oper at the back contact of either relay 15 or 35, as the case may be, until the other subscriber hangs up.

Assuming however, that both subscribers have replaced their receivers on their respective hooks, relays 15 and 255 will both be deenergized and a circuit will be closed from battery through release magnet 33, ofi'-normal contact 34, back contact and outermost armature of relay 35. back contact and right armature of relay 21 and the back contact and right armature of relay 15 to ground,

thus causing the return to normal of the connector switch.

The advantages of the present invention are obvious, as it permits the capacity of a connector switch to be doubled without an increase in the operating circuit therefor, with the exception of the brush selecting relay 17 and the controlling circuits therefor. Zilhis efiects a great saving in operating magnets in an exchange system. It is also equally obvious that the invention is readily applicable to switches and circuits there tor which diti'er very widely from those herein described. In fact this invention may be readily applied to nem'ly all types of switching apparatus and the controlling circuits therefor.

What is claimed is;

'1. In a telephone system. a switch, a pinrality of sets of correspoiulingly positioned brushes on said switch, a seriesotsetsolcontacts for each ot" said sets of brushes. a connecting circuit extending to said switch. multiple terminal contacts for said connects inc. circuit. a switching device arranged for connection to said terminal contacts. brush selecting means for rendering operative one or another of said sets of brushes. an electromagnct lor operating said brush selecting means. and a circuit for said magnet extending llH'tHIfIll one of said terminal contacts and the corres mnding movable contact 01' said switching device.

2. In a telephone system, a switch, a. plurality of sets of correspondingly positioned brushes on said switch. a series of sets of contacts for each of said sets of brushes, a connecting circuit extending to said switch, multiple terminalcontacts for said connectinc circuit, a relay to the back contacts of which one of sad brush sets is connected, the other brush set ein connected to the front contacts of 'said relay, a circuit for said relay automatically completed when connection is made to certain ot'said multiple terminal sets. and a locking circuit for said relay. includingan armature thereof and an oll'aiornnll contact of said switch.

3. In a telephone system, a switch a brush 30 support for said switch, a plurality of correspondingly positioned brush sets on said support. series of contact sets. one for each brush. means for moving said support to cause said brushes to simultaneously traverse 35 said contacts, a connecting circuit extending to said switch. two series of multiple terminals for said circuit, a relay normally tending to render one of said brush sets operative, and means for operating said relay when said switch is selected at any one of the terminals in one of said series to render the other brush set ope 'ative.

in a telephone system, a switch, a plurality oi brushes on said switch. an electromagnet for rendering" ope 'ative one or another of said brushes. a connecting circuit extending to said switch, two series of multiple terminals for said connecting: circuit at which said circuit may be selected. and means whereby the operation of said magnet is governed in accordance with which of said series ot multiple terminals said switch is selected at.

5. in a telephone system. a switch, a plurality of sets of correspondiugly positioned brushes on said switch. a series of sets of contacts t'or each of" said sets of brushes, a. connecting circuit extending to said s two series of multiple terminal (OnllcIS Ioi said connecting circuit. a switching device arrangml for connection to said terminal 1 tacts. brush selecting means for rendering operative one or another of said sets of brushes. an electromagiwt for op atiug said brush selecting means. a circuit for said mag"- net. and means for completing said circuit when said switching device makes connection to any of the terminal contacts in one of said series.

(1. in a telephone system. a switch. a plurality of sets of correspondingly positioned brushes on said switch. :2 series of sets of contacts for arch of said sets of brushes, a connecting circuit extending to said switch, two series ot multiple terminal contacts for said connecting circuit. a magnet arranged to render one of said brush sets operative when denergized, the other brush set being 'madeoperative when said magnet is energized, and a circuit for said magnet automatically completed when connectlon is made to any one of the multiple terminal sets of one of said series.

7. In a telephone system, a switch, a plurality of sets of correspondingly positioned brushes on said switch, a series of sets of con tacts for each of said sets 0t brushes, a connecting circuit extending to said switch, multiple terminal contacts for said connecting circuit, a relay arranged to render one of said brush sets operative when said relay is deenergized, the other brush set beingrenderecl operative when said relay is energized, a circuit for said relay automatically completed when connection is made to certain of said multiple terminal contacts, and a locking circuit for said relay, including an armature thereof and an ofi-normal contact of said switch.

8. In a telephone system, a switch, a brush support for said switch, a plurality of correspondingly positioned brush sets on said support, series of contact sets, one for each brush set, means for moving said support to cause said brushes to simultaneouslytraverse said contacts, a connecting circuit extending to said switch, two series of multiple terminals for said circuit at which said switch may be selected, a relay normally tending to render one of said brush sets operative, a circuit for said relay, and means for closing said circuit when said switch is' selected at any one of the terminals in one of said series to render the other brush set operative.

9. In a telephone system, a switch, a plurality of brushes on said switch, a relay for rendering operative one or another of said brushes, :1 connecting circuit extending to said switch, two series of multiple terminals for said connecting circuit at which said circuit may be selected, means whereby the operation of said relay is governed by which of said series of multiple terminals said switch is selected at, two sources of ringing current of difierent characters, sai'd sources being connected to the front and back contacts respectively of said relay.

10. In a telephone system, a switch, a plurality of brush sets on said switch, series of contacts, one for each of said brush sets, a relay for selecting one or another of said brush sets to make connections to a wanted line, a plurality of sources of ringing current of different characters, and means controlled by said relay for determining which of said sources of current will be connected to a wanted line.

In witness whereof, I hereunto subscribe my name this 10th day of February, A. D.

. OWEN E. HILL. 

